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Eprom Eraser, how to build

Discussion in 'Electronic Repair' started by 123, Nov 9, 2005.

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  1. 123

    123 Guest

  2. N Cook

    N Cook Guest

    Somewhere on the 2 tips files on URL below is
    tip for converting a small sun tan lamp
     
  3. Franc Zabkar

    Franc Zabkar Guest


    "An 'anti-bacterial' toothbrush holder (AU$25), a single capacitor and
    a simple IC carrier are all you need for a fully-functioning EPROM
    eraser."

    http://www.siliconchip.com.au/cms/A_104058/article.html


    -- Franc Zabkar

    Please remove one 'i' from my address when replying by email.
     
  4. You have to pay to read that article!?!??
     
  5. Andy

    Andy Guest

    Is it possible to build an inexpensive UV EPROM ERASER out of those
    innexpensive UV LED Flashlights or the bulb from a bug zapper such as
    this one:

    Andy writes:

    No. The frequency of the emission of a UV LED is far removed from
    the
    particular NARROW band of UV frequencies that can erase an EPROM...

    I forget the actual center frequency needed for EPROM erasure, but if
    the
    spectral frequency is not very very close to it, the EPROM won't erase.
    If you research it on the internet, you will learn a great deal...

    For instance RF is RF, but an AM radio is not sensitive to TV
    channels...

    Same with UV, which covers a very wide spectral range. An EPROM is
    like
    a little , tuned, receiver.....

    If I remember correctly, the germicical lamps will put out the proper
    UV
    frequency. They are fairly expensive, tho....... UV LEDs are
    definitely
    NOT near the proper frequency range......

    Andy
     
  6. Andy

    Andy Guest

    Andy replies even more:

    I just remembeedr that the EPROM frequency is 253.7 nanometers.

    Here is a website that tells about how the erasers work. It should
    answer your questions.

    http://xtronics.com/memory/how_EPROM-works.htm


    If you build yourself one, and can find a cheap source for parts,
    please
    post it on this newsgroup. I've been wanting to do this for some
    time, myself, but am just too damn lazy to go to the trouble for
    something
    I'll only use once a year....... Thanks, and good luck

    Andy
     
  7. Sjouke Burry

    Sjouke Burry Guest

    Could You refrain from giving links where you can only read the
    first few lines,and have to pay $$$ fro the rest???
    Unless of course you want to spam for a commercial URL.

    Burry.
     
  8. I can attest to that, the sun lamp works great & can be bought from a charity
    shop or yard sale for about $2.


    --

    Australia isn't "down under", it's "off to one side"!


    www.cobracat.com (home of the Australian Cobra Catamaran)
    http://groups.yahoo.com/group/cobra-cat/
     
  9. James Sweet

    James Sweet Guest


    Couple weeks ago Fred Meyers had germicidal tubes for Hamilton Beach air
    purifiers on sale, one of those would work nicely with a small
    fluorescent inverter such as those used in cheap battery powered
    under-cabinet lights.
     
  10. James Sweet

    James Sweet Guest


    It's the whole magazine available online, you should be able to preview
    a few articles for free every once in a while. There's a trick you can
    use to view any of them free at any time too.
     
  11. James Sweet

    James Sweet Guest


    Why? He doesn't work for the magazine.

    Just do a search in Google for the first line of text from the article
    and access it from there, you'll be able to read the whole thing. Not
    sure why you didn't get to preview it unless you're on dialup and
    someone with your IP recently read it.
     
  12. Franc Zabkar

    Franc Zabkar Guest

    Sorry. The bulk of the article basically describes how to increase the
    time constant of the circuit by adding a large capacitor in parallel
    with the existing one. That's about it.

    -- Franc Zabkar

    Please remove one 'i' from my address when replying by email.
     
  13. Andy

    Andy Guest

    Could You refrain from giving links where you can only read the
    first few lines,and have to pay $$$ fro the rest???
    Unless of course you want to spam for a commercial URL.--- Sjouke



    Andy comments:

    I have just wasted more time reading your personal net police
    reply than I have on following the rest of this thread. Thank you
    for trying to teach me patience , tolerance, and understanding. You
    didn't go a good job of it , tho.....

    Andy
     
  14. Mark Zenier

    Mark Zenier Guest

    And a lot of what you learn will be WRONG.

    An EPROM cell will get erased by any electromagnetic radiation shorter
    in wavelength than some limit determined by the device physics. (You can
    even use X-Rays is you can find a source powerful enough).

    But that wavelength is shorter than the 350 nanometer output of a lot of
    UV lamps. Ie. the /BL or /BLB "poster lights" that are relatively safe.
    These can light up the phosphorescent ink on posters, cure glue or
    printed circuit etch resist, but not erase EPROMs. (Or at least not in
    any reasonable length of time. Back in my starving student days I did
    it with a poster lamp, but not many people want to wait for 3 1/2 days).

    A 300 nanometer tanning bed lamp will do it in about an hour, a 258 (?)
    nanometer germicidal lamp in just a few minutes. In other words,
    if you can't get a sunburn or worse, it won't erase an EPROM.

    Mark Zenier
    Googleproofaddress(account:mzenier provider:eskimo domain:com)
     
  15. spudnuty

    spudnuty Guest

    I have one that I found in a pile of electronics stuff that was tossed.
    I always was gonna do some projects with it but..... It's a Prometrics
    Model 117. It has a mechanical timer that controls exposure. It works
    but I pulled the power cord for some other project. I'd be glad to send
    this to someone who could use it if they'd pay the shipping. eMail me
    for pics and arrangements: spudnuty<at>aol<dot>com.

    Richard
     
  16. Asimov

    Asimov Guest

    "Mark Zenier" bravely wrote to "All" (11 Nov 05 03:41:15)
    --- on the heady topic of "Re: Eprom Eraser, how to build"

    MZ> From: (Mark Zenier)
    MZ> Xref: core-easynews sci.electronics.repair:348213

    MZ> And a lot of what you learn will be WRONG.

    MZ> An EPROM cell will get erased by any electromagnetic radiation shorter
    MZ> in wavelength than some limit determined by the device physics. (You
    MZ> can even use X-Rays is you can find a source powerful enough).

    MZ> But that wavelength is shorter than the 350 nanometer output of a lot
    MZ> of UV lamps. Ie. the /BL or /BLB "poster lights" that are relatively
    MZ> safe. These can light up the phosphorescent ink on posters, cure glue
    MZ> or printed circuit etch resist, but not erase EPROMs. (Or at least not
    MZ> in any reasonable length of time. Back in my starving student days I
    MZ> did it with a poster lamp, but not many people want to wait for 3 1/2
    MZ> days).
    MZ> A 300 nanometer tanning bed lamp will do it in about an hour, a 258
    MZ> (?) nanometer germicidal lamp in just a few minutes. In other words,
    MZ> if you can't get a sunburn or worse, it won't erase an EPROM.


    An alternative is the warm midday sun in the summer. Someone tried to
    convince me I could leave an eprom out on the beach for years and it
    wouldn't erase but that was bs as anyone who gets a sunburn can attest.
    I exposed pcb's outdoors in my early experiments. It took about 12
    minutes under the Sun compared to about 2 minutes with a proper lamp.

    A*s*i*m*o*v

    .... Puddy-tat's not so bwave in Gwanny's microwave!
     
  17. Chris Jones

    Chris Jones Guest

    I tried eresing EPROMs in the sun, in Australia (i.e. proper sunlight).
    From what I can remember, it took more than a week. That makes me very
    scared of looking into one of those eraser tubes which can do it in
    minutes. PCB resist uses longer, less dangerous wavelengths.
    Chris
     
  18. Asimov

    Asimov Guest

    "Chris Jones" bravely wrote to "All" (13 Nov 05 15:06:55)
    --- on the heady topic of "Re: Eprom Eraser, how to build"

    CJ> From: Chris Jones <>
    CJ> Xref: core-easynews sci.electronics.repair:348423

    CJ> I tried eresing EPROMs in the sun, in Australia (i.e. proper
    CJ> sunlight). From what I can remember, it took more than a week. That
    CJ> makes me very scared of looking into one of those eraser tubes which
    CJ> can do it in minutes. PCB resist uses longer, less dangerous
    CJ> wavelengths. Chris


    Okay, thanks for the heads up on that one. I'd like to be an eprom on
    an Australian beach any day, as we're headed for winter here soon. In
    the early 70's my roomy fell asleep under a tanning lamp. The skin was
    as red as a cooked lobster's and then peeled off in swatches for days
    after that. Not a pretty sight that lady was.

    A*s*i*m*o*v

    .... Anyone not wearing 2,000,000 sunblock is gonna have a REAL_ BAD_ DAY_7
     
  19. Ian French

    Ian French Guest

    Hi all,

    For a real, serious, and cheap solution to erasing EPROMS try this link
    http://www.rampantapathy.co.uk/epromeraser.html

    He uses a 6 inch long, 4 Watt, Germicidal lamp in conjunction with a "Maplin
    Torch", which in its normal state contained a normal flourescent tube.
    The lamps are available from http://www.firstlightdirect.com/, and work out
    to about £8.50 each including Postage and VAT.
    I have just recently used a similar set up with a 9 inch tube and it works
    fine, erasing the EPROM in about 10 minutes when place 0.5 inch from the
    tube.
    If any of you do this BE SURE to place the tube etc inside a light proof box
    BEFORE switching the power on, this Wavelength of UV ( about 250
    nanometres) is DANGEROUS to your eyesight.
    I have found that a cardboard Boxfile is OK.
    Bye,

    Ian.
     
  20. Guest

    If you just need one or two eproms erased, go to wal-mart and cram them
    up in the bottled water purifier at the front door. Pick them up on
    your way out. :)
     
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